I did not want to use wood. It is easy. So I thought of something else. This piece [full round] of pipe left over from the sanitary work was ready to be thrown away as junk. But no. I cannot throw. I had to 'unjunk' it with something. I had nice old brass hooks. I thought why not cut it up. Exact half will render it difficult to nail it to the wall. It was a 110 mm diameter pipe. So, I chose to cut at the place where I get a smaller piece that is less than half the diameter. This way, the place where I want to nail it will be nearer to the wall. Now it was ready to make holes for hooks.
Exact places were marked where the hooks had to be screwed in. Also made two holes for the nails that were to be driven into the wall to fix this key holder. Even screws will work, but in my case, nails were enough.
Presto, the key holder was ready. From time to time, cleaning the top half of this is a must as it collects dust - no exception. But the hollow of the pipe has to be cleaned with a vacuum cleaner. This is the only disadvantage. But this hole also can be covered to prevent dust entering. But I have left it open.